Modern vehicles are often equipped with aftertreatment systems that are designed to treat post-combustion exhaust gases prior to tailpipe emission. On vehicles with diesel engines, the aftertreatment system can reduce combustion by-products such as particulate matter (PM) and nitrous oxide (NOx) from exhaust gases. Diesel aftertreatment systems may employ various devices including a diesel oxidation catalyst (DOCs), a diesel particulate filter (DPF), a selective catalytic reduction unit (SCR), ammonia oxidation catalysts (AOCs) and combinations thereof to reduce PM and NOx.
In general, exhaust gas treatment devices are designed to operate at relatively high temperatures that are commensurate with the temperature of the post-combustion exhaust gases. Accordingly, catalysts need to reach their respective operating temperatures to effectively and efficiently reduce emissions from the exhaust gases. As heated exhaust gases pass through the catalysts of the aftertreatment system, the catalysts are heated up from a starting or ambient temperature to an effective operating temperature range. In order to reduce emissions and shorten the warm up time, the aftertreatment device may include an electrical heater that uses electrical power to more rapidly heat the catalyst thereby reducing the length of time for the device to reach the effective operating temperature. However, on-board electrical energy is a highly managed resource that must be generated either by the engine as fueled electrical energy or recovered from vehicle motion as unfueled electrical energy.
Accordingly, it is desirable to provide systems and methods to control power for an electrically heated catalyst while improving overall engine efficiency by managing the operation of the electrically heated catalyst. These systems and methods should improve overall vehicle fuel economy while still reducing the emission of combustion by-products from the exhaust gases. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.